n The act of receiving anything from a source; the act of procuring an effect from a cause, means, or condition, as profits from capital, conclusions or opinions from evidence.
n The act of tracing origin or descent, as in grammar or genealogy; as, the derivation of a word from an Indo-European root.
n (mathematics) The operation of deducing one function from another according to some fixed law, called the law of derivation, as the of differentiation or of integration.
n (medicine) A drawing of humors or fluids from one part of the body to another, to relieve or lessen a morbid process.